This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. To maximize therapeutic effects, controlled localizaiton of nucleic acids (e.g., DNA and RNA) in appropriate intracellular targets is required. We formed fluorescently labled polyplexes with cationic polymer and plasmid DNA. We observed the intracellular pathway of polyplex particle in a NIH 3T3 cell using 3D-particle tracking instrument.